The first commercial MIPS CPU model, the R2000, was announced in 1985 as a 32-bit implementation. It was followed by the R3000, the first successful MIPS design in the marketplace with more than 1 million processors made. The R3000 was used in high-end UNIX computers by Siemens and DEC and in the Silicon Graphics SGI Personal IRIS 4D/20 graphic workstations. On this machines 3D sequences for movies like The Abyss, Jurrasic Park or Terminator 2 were rendered.
The R3000 has an interface to handle 3 coprocessors. Each coprocessor has a flag line connected with the CPU that can be tested and a conditional branch executed dependent on its value. Coprocessor instructions can be executed directly from the instruction stream.
Coprocessor 0 (CP0) is incorporated on the CPU chip and supports the virtual memory system and exception handling. It is also referred to as the System Control Coprocessor.
CP1 is reserved for the floating point coprocessor. An FPU is mandatory for most R3000 systems. CP2 is available for specific implementations and is often used to accelerate memory access by connecting it to an R3020 memory buffer or an R3220 read/write buffer chip. Later versions of the R3000 (R3000A) had built in memory buffer circuitry.
Reference:
R3000 at SGIstuffR3000 information (German)

The R3010 is the FPU for the MIPS R3000 CPU. It provides high-speed floating point capability for systems based on the R3000 CPU. The organization of the FPU architecture is similar to that of the R3000 CPU, and allows for optimization of both integer and floating-point performance.
The R3010 FPU connects seamlessly to the R3000 CPU via the R3000 coprocessor interface CP1, and since both units receive instructions in parallel, floating-point instructions can be initiated at the same single cycle rate as fixed-point instructions.